FRANKFURT. Pet
owners have been sure of this for long time, and scientific research provides
confirmation: animals, too, have personalities. A study originating at Goethe
University documents that even with regard to fish, their own personality traits
and that of their potential partner is critical when selecting a “groom”.
Individual animals, from vertebrates to
crabs and spiders, exhibit consistent behaviour tendencies that distinguish
them from other members of their species. The most thoroughly researched
personality trait in the animal world is propensity for risk-taking. A wide
range of individuals, from very shy to quite courageous, can be found among the
small freshwater fish Poecilia mexicana, which live primarily in the rivers of
Mexico. Both traits can be of advantage: while shy fish have a lower risk of
being eaten by predatory fish and birds, bold ones are often more efficient at
finding food.
Risk-taking males also have advantages
when it comes to choosing a partner, as shown in a study by Dr. Carolin
Sommer-Trembo and other scientists at Goethe University. Using behaviour tests,
males and females were first classified on a scale from shy to bold. A partner
selection test followed, in which females were allowed to choose between two
males with different risk-taking propensities. To prevent the females from
being too strongly affected by other criteria, the males were selected so that
they were almost identical in their external characteristics such as body
shape, colouration and size.
The results seemed clear: bold males were
preferred. But at second glance, the risk appetite of the females also played a
role in the decision. Bold females exhibited the strongest preference for bold
males, while this preference was weaker among shy females. Are courageous males
more attractive to all females, or do less courageous males also have chance,
since “birds of a feather flock together”? The study shows that these two
mechanisms are intertwined and, as is so often the case, the truth is not a
case of “either/or” but of “both/as well as”.
Publication:
Sommer-Trembo C, Schreier M, Plath M
(2020) Different preference functions act in unison: mate choice and
risk-taking behaviour in the Atlantic molly (Poecilia mexicana). Journal of
Ethology, DOI: 10.1007/s10164-020-00643-5
Images may be downloaded at: http://www.uni-frankfurt.de/86091187
Caption: The female Atlantic molly is not very colourful,
while the tail fins of the male glow in various shades of yellow and orange (Credits:
Claudia Earp (Fishes1 and 2) / Martin Plath (Fishes3))
Further
information: Carolin Sommer-Trembo, Postdoc, Zoological
Institute of the University of Basel, Vesalgasse 1, 4051 Basel, Telefon: +41
(0) 783079999, Email: sommer-trembo@gmx.de